<b>Abstract</b>: David Robbins observed that a “condensation” algorithm for
calculating determinants due to Charles Dodgson (a.k.a. Lewis Carroll)
has, empirically, a curious stability property when computed with
finite-precision p-adic arithmetic. The purpose of this talk is to
explain this conjecture, give a generalization to cluster algebras, prove
some instances of that generalization, and show that a purely algebraic
conjecture about certain deformations of cluster algebras implies all of
these conjectures. Somos sequences will be used as a running example.
The results are joint work with Kiran Kedlaya.

Refreshments will be served in 348 Avery 3:30-4:00 PM.
The talk is free and open to the public.